The requirements of data processing systems for electrical power continue to grow, both in new systems being designed and in existing systems in the field. Most of the rising requirement result from increased processor capability and increased power demand by memory. The power requirements will, on occasion, exceed the capability of power supplies associated with processing elements such as systems.
In server applications, this has been handled by providing redundancies. That is, processing elements such as blades in a blade server will be grouped with power supplies into power domains. Each domain will have one or more processing elements such as blades and at least two power supplies associated with the grouped processing elements. The power supplies work together to supply the voltages and currents required by the processing elements.
Systems with such N+1 or N+N power supply schemes are known. However, if one power supply shuts down, as by loss or electrical supply or failure, then the system may fail. Some newer processing elements address such problems by providing for throttling down, also sometimes known as power fold back. This is helpful in reducing the power requirement of a domain to that which can be supplied by a single supply, but takes time. There can be sufficient time if line power is lost, as most power supplies typically have a hold up interval. However, if one supply fails, there may be no holdup time available and so over current protection may be tripped in remaining power supplies.